Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna

Magneto-electric dipole (ME-dipole) antennas offer several advantages, including wide impedance bandwidth, stable high gain, unidirectional radiation, and low back-lobe radiation patterns, making them suitable for modern wireless communication systems. However, the thickness of conventional ME-dipol...

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Main Authors: Khalid Almegbel, Kin-Fai Tong
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/25/4/1234
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author Khalid Almegbel
Kin-Fai Tong
author_facet Khalid Almegbel
Kin-Fai Tong
author_sort Khalid Almegbel
collection DOAJ
description Magneto-electric dipole (ME-dipole) antennas offer several advantages, including wide impedance bandwidth, stable high gain, unidirectional radiation, and low back-lobe radiation patterns, making them suitable for modern wireless communication systems. However, the thickness of conventional ME-dipole antennas is typically about a quarter wavelength (0.25<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mo>λ</mo><mi>o</mi></msub></semantics></math></inline-formula>) at the center operating frequency, which may not be desirable for portable device applications. This work introduces a new feeding method that reduces the antenna profile and ground plane size while maintaining the same advantages. A suspended horizontal line is proposed to excite the cavity-less ME-dipole antenna through proximity coupling. The measured results demonstrate a wide impedance bandwidth of 45.3% (ranging from 2.05 GHz to 3.25 GHz) and an average in-band gain of 9 dBi with stable <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>1</mn></mrow></semantics></math></inline-formula> dBi in-band variation with a ground reflector of size about 0.89<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msubsup><mo>λ</mo><mi>o</mi><mn>2</mn></msubsup></semantics></math></inline-formula>. More importantly, the cavity-less design reduces the overall thickness of the antenna to 0.17<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mo>λ</mo><mi>o</mi></msub></semantics></math></inline-formula> at the center operating frequency.
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spelling doaj-art-778d6990c5a24f74ade53c8644fd645e2025-08-20T02:45:01ZengMDPI AGSensors1424-82202025-02-01254123410.3390/s25041234Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole AntennaKhalid Almegbel0Kin-Fai Tong1Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UKDepartment of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UKMagneto-electric dipole (ME-dipole) antennas offer several advantages, including wide impedance bandwidth, stable high gain, unidirectional radiation, and low back-lobe radiation patterns, making them suitable for modern wireless communication systems. However, the thickness of conventional ME-dipole antennas is typically about a quarter wavelength (0.25<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mo>λ</mo><mi>o</mi></msub></semantics></math></inline-formula>) at the center operating frequency, which may not be desirable for portable device applications. This work introduces a new feeding method that reduces the antenna profile and ground plane size while maintaining the same advantages. A suspended horizontal line is proposed to excite the cavity-less ME-dipole antenna through proximity coupling. The measured results demonstrate a wide impedance bandwidth of 45.3% (ranging from 2.05 GHz to 3.25 GHz) and an average in-band gain of 9 dBi with stable <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>1</mn></mrow></semantics></math></inline-formula> dBi in-band variation with a ground reflector of size about 0.89<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msubsup><mo>λ</mo><mi>o</mi><mn>2</mn></msubsup></semantics></math></inline-formula>. More importantly, the cavity-less design reduces the overall thickness of the antenna to 0.17<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mo>λ</mo><mi>o</mi></msub></semantics></math></inline-formula> at the center operating frequency.https://www.mdpi.com/1424-8220/25/4/1234proximity coupledsuspended coupling linewidebandstable high gainmagneto-electric dipoles
spellingShingle Khalid Almegbel
Kin-Fai Tong
Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna
Sensors
proximity coupled
suspended coupling line
wideband
stable high gain
magneto-electric dipoles
title Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna
title_full Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna
title_fullStr Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna
title_full_unstemmed Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna
title_short Low-Profile Proximity-Coupled Cavity-Less Magneto-Electric Dipole Antenna
title_sort low profile proximity coupled cavity less magneto electric dipole antenna
topic proximity coupled
suspended coupling line
wideband
stable high gain
magneto-electric dipoles
url https://www.mdpi.com/1424-8220/25/4/1234
work_keys_str_mv AT khalidalmegbel lowprofileproximitycoupledcavitylessmagnetoelectricdipoleantenna
AT kinfaitong lowprofileproximitycoupledcavitylessmagnetoelectricdipoleantenna